温度及pH敏感水凝胶的合成及性能研究

研究了pH值敏感聚丙烯酸水凝胶的合成工艺及敏感性.详细研究了单体、摩尔比、引发剂用量、聚合温度、交联剂用量对温度及pH敏感聚(丙烯酸)-CO-(丙烯酰胺)水凝胶的收率及敏感性的影响.交联剂用量对溶胀比影响最显著,引发剂用量对收率影响最大.     

F68大单体/HEMA共聚水凝胶的制备及性能研究（Ⅱ）：pH敏感性

以Pluronic F68与甲基丙烯酸缩水甘油酯（GMA）反应制备可光聚合的F68/GMA大分子单体,再在水溶液中与pH敏感性丙烯酸（AA）单体和甲基丙烯酸β-羟乙酯（HEMA）经紫外光原位聚合制备温度敏感水凝胶。详细地研究了水凝胶在不同pH下的溶胀性能。溶胀动力学测量的结果表明：该水凝胶在具有温度响应性的同时还具有pH响应性且具有可逆性。     

电子束辐射制备pH敏感性聚乙烯醇水凝胶

应用电子束辐射交联技术制备了聚乙烯醇接枝丙烯酸(PVA-g-AAc)水凝胶。研究了pH值、AAc单体用量和辐照剂量等因素对PVA-g-AAc水凝胶溶胀率的影响。实验结果表明,在1 697cm-1处,PVA-g-AAc水凝胶的红外光谱图上出现强烈的羰基的C O特征峰,表明AAc成功接枝到PVA分子上;PVA-g-AAc水凝胶的溶胀率随PVA/AAc/H2O中AAc的质量分数和浸泡时间增加而增大;在pH=9.2时,PVA-g-AAc水凝胶具有显著的pH敏感性;辐射剂量为15kGy时,由PVA/AAc/H2O(1/1/20,质量比)混合溶液制备的PVA-g-AAc水凝胶具有较高的溶胀率;辐射剂量为5kGy时,由PVA/AAc/H2O(1/5/20,质量比)混合溶液制备的PVA-g-AAc水凝胶具有较高的溶胀率。     

F68大单体/HEMA共聚水凝胶的制备及性能研究(Ⅰ):温度敏感性

本文以温度敏感性Pluronic F68与甲基丙烯酸缩水甘油酯(GMA)反应制备可光聚合的F68/GMA大分子单体,再在水溶液中与丙烯酸(AA)单体和甲基丙烯酸β-羟乙酯(HEMA)经紫外光原位聚合制备温度敏感水凝胶。详细地研究了水凝胶在不同温度下的溶胀性能。溶胀动力学测量的结果表明,该水凝胶具有温度响应性且具有可逆性。     

PEGDA/NIPAM共聚物水凝胶的溶胀性能及体积相变研究

以IRGACURE2959为光引发剂,聚乙二醇双丙烯酸酯(PEGAD)和N-异丙基丙烯酰胺(NIPAM)为单体,通过紫外光引发光聚合合成了PEGDA/NIPAM共聚物水凝胶.研究了不同单体质量比凝胶材料在不同温度和pH值下的溶胀性能,测试凝胶在不同温度水中的体积相变.研究结果表明,水凝胶的平衡溶胀率随着NIPAM质量浓度增大而增大,随着环境温度的升高而减小,随着环境pH的增大而增大;NIPAM引入后,随着温度升高达到凝胶低临界溶解温度(LCST)时,凝胶平衡溶胀率及溶胀比减小明显加快,发生体积相变;随着NIPAM质量浓度的增大,凝胶溶胀饱和率减小,凝胶具备良好的延缓溶胀性能.     

环境响应型智能高分子凝胶

结合智能高分子凝胶的发展现状介绍笔者近几年的研究成果：由温度敏感型N-异丙基丙烯酰胺(NIPAM)与氯化三甲基-3-丙烯酰胺丙基胺(DMAPAA-Q)构成的共聚阳离子凝胶具有LCST特性和很好的溶胀性能，而半互穿温敏凝胶PDMAPS／PAMPS显示UCST特性，且在UCST附近不发生体积变化；将侧链含偶氮苯基的丙烯酰胺基偶氮苯单体(AAAB)与丙烯酸(AA)共聚合成了一种新型功能高分子P(AA-co-AAAB)。具有pH和光双重响应性能；合成的导电聚(3-羧甲基噻吩)(F3TAA)水凝胶具有pH敏感性，且用高氯酸作掺杂剂对水凝胶的掺杂行为进行研究发现，高氯酸极易使聚噻吩凝胶掺杂，而且一旦掺杂则在掺杂状态下具有相对的稳定性。     

聚丙烯酸盐水凝胶的制备

以丙烯酸镁和丙烯酸钙为单体,乙二醇二丙烯酸酯为交联剂制备了聚丙烯酸盐水凝胶,对其结构、形态和溶胀性能进行了研究.实验表明:聚丙烯酸盐水凝胶具有相互连通的孔洞结构;交联剂的用量是影响水凝胶溶胀速率和溶胀度的一个重要因素,当交联剂用量较低时,水凝胶显示出较快的溶胀速率和较大的溶胀度;聚丙烯酸盐水凝胶具有明显的温度敏感性和pH敏感性.     

含羧酸根基团智能凝胶的合成和电场行为研究

利用化学交联法，以过硫酸胺（APS）为引发剂，以N，N＇-亚甲基双丙烯酰胺（BIS）为交联剂，制备丙烯酰胺（AM）、丙烯酸（AA）共聚凝胶，初步探索凝胶在NaCl溶液中直流电场作用下的溶胀、弯曲行为．讨论了电压和电解质溶液浓度对凝胶弯曲行为的影响，凝胶在蒸馏水和盐水中的溶胀率，以及丙烯酸加入质量对P（AA-AM）凝胶溶胀率的影响，凝胶的溶胀率在pH值7左右出现最大值。     

聚衣康酸/聚N-异丙基丙烯酰胺IPN水凝胶的研究

以具有pH敏感性的聚衣康酸网络为基础，利用分步互穿聚合物网络（IPN）技术引入了另一具有温度敏感性的聚N-异丙基丙烯酰胺网络，制得了一种新的全IPN型水凝胶，对其溶胀性能进行研究，发现其在25～45℃的温度区域表现出明显的收缩特性，且随着pH增加，凝胶的溶胀率变大。这表明聚衣康酸／聚N-异丙基丙烯酰胺互穿网络水凝胶具有温度及pH双重敏感特性。     

聚衣康酸/聚丙烯酸互穿网络水凝胶的研究

以聚衣康酸（PIAc）网络为基础，通过分步互穿聚合物网络（IPN）技术引入了聚丙烯酸（PAAc）网络，制得了一种新的由具有同种官能团的2种聚合物互穿而成的全IPN水凝胶。通过研究聚衣康酸水凝胶、聚丙烯酸水凝胶和IPN水凝胶在不同pH条件下的溶胀性能，发现3种水凝胶随着pH增加，溶胀率变大，均表现出pH敏感性。IPN水凝胶的溶胀规律与聚衣康酸、聚丙烯酸水凝胶的溶胀规律相比有明显的差别。     

聚醚-壳聚糖水凝胶溶胀性能的研究

以壳聚糖和聚醚为原料,戊二醛为交联剂,在醋酸溶液中合成了聚醚-壳聚糖水凝胶.研究了凝胶温度、聚醚与壳聚糖的质量比、交联剂浓度等对半互穿网络水凝胶溶胀性能的影响,并采用正交实验对工艺条件进行了优化.实验结果表明:反应温度为45℃,聚醚和壳聚糖的质量比为0.4,戊二醛浓度为0.05 mol/L,其凝胶溶胀度最大.聚醚-壳聚糖凝胶是pH敏感性水凝胶.     

聚乙烯醇-聚丙烯酰胺互穿网络水凝胶的制备及吸附性能

采用聚乙烯醇(PVA)、聚丙烯酰胺(PAM)为原料,戊二醛(glutaraldehyde)为交联剂,制备了一种互穿网络(IPN)水凝胶。用傅立叶红外光谱仪对其结构进行表征,研究了PVA和PAM按不同配比及交联剂的不同用量制备的IPN水凝胶的吸水性和Cu²⁺的吸附性,主要探讨了吸附时间、pH、吸附温度等对吸附Cu²⁺的影响,分析了吸附行为及其动力学特性,并对其吸附机理做出了初步探讨。结果表明：在本实验研究范围内,30wt.% PAM含量的PVA-PAM IPN水凝胶在pH=5时对Cu²⁺的吸附效果最佳;在一定温度范围内,PVA-PAM IPN水凝胶对Cu²⁺的平衡吸附量随温度升高而增大;吸附行为符合准一级和准二级动力学方程,扩散机制为颗粒内扩散和膜扩散双重作用。     

Preparation and swelling behaviors of rapid responsive semi-IPN NaCMC/PNIPAm hydrogels

Semi-interpenetrating network(semi-IPN) hydrogels composed of sodium carboxylmethylcellulose(NaCMC) and poly N-isopropylacrylamide(PNIPAm) were prepared by free radical polymerization of N-isopropyl acrylamide(NIPAm) in dimethylsulfoxide(DMSO) in the presence of NaCMC. The structures of hydrogels were characterized by Fourier transform infrared spectroscopy(FTIR), scanning electron microscopy(SEM) and differential scanning calorimetry(DSC). SEM images show that the hydrogels present porous network structures. Most water in the hydrogels were free water and freezing water. The equilibrium swelling ratio(ESR) and swelling rate(SR) were quite different at various swelling temperature. ESR of the hydrogels ranged abruptly from 15.2 g/g to 1.56 g/g and the hydrogels changed from transparent into opaque with swelling temperature changing from 33 ℃ to 34 ℃, that is to say, the hydrogels exhibited the good temperature sensitivity at about 33 ℃ similar to low critical solution temperature(LCST) of pure PNIPAm, swelling rate were very different at below and above LCST due to hydrogel swelling with different swelling mechanism. Moreover, the semi-IPN hydrogels swelled much rapidly than pure PNIPAm hydrogels did at room temperature, the equillibrium swelling ratio(ESR) and swelling rate of the hydrogels increased with increasing of NaCMC content, i e. It is suggested that NaCMC could be potential for preparation of porous and rapid swelling hydrogels     

PVA/PAA/BC复合水凝胶的制备与性能

利用冰冻-解冻循环法制备聚乙烯醇（PVA）/聚丙烯酸（PAA）/细菌纤维素（BC）复合水凝胶.研究BC与单体丙烯酸（AA）用量对PVA/PAA/BC复合水凝胶的力学性能和溶胀特性的影响,初步探讨PVA/PAA/BC复合水凝胶的pH敏感性.实验结果表明：随着BC添加量的增多,PVA/PAA/BC复合水凝胶的含水率和拉伸强度与PVA/PAA水凝胶相比均有一定程度的提高,SEM表明复合水凝胶的网络交联点增多;加入AA会使复合水凝胶拉伸强度减小,但溶胀性能提高很多.综合考虑,BC添加量为4%,AA添加量为8%时,各项性能均较好.     

海藻酸钠/氧化石墨烯复合水凝胶的制备与性能

为了研究氧化石墨烯（GO）对海藻酸钠（SA）凝胶性能的影响,以Ca2+与Fe3+作为交联剂,在SA水凝胶自组装过程中加入GO水溶液,一步法得到了海藻酸钠/氧化石墨烯（SA/GO）复合水凝胶。通过扫描电子显微镜与X射线衍射表征了所得凝胶的结构与微观形貌,测试了不同凝胶样品的平衡溶胀性能和力学性能。研究结果表明,Fe3+交联得到的凝胶结构相比Ca2+交联得到的凝胶更加紧凑,平衡溶胀性能降低较多;随着GO的加入,复合水凝胶的力学性能提升,平衡溶胀性能降低,这表明SA/GO复合水凝胶的性能可以通过选择合适的交联剂与GO用量进行调控。关键词:海藻酸钠;氧化石墨烯;复合水凝胶     

Synthesis and property of temperature and pH sensitive xanthan-MA/PNIPAAm hydrogels

A novel class of xanthan-maleic anhydride (Xan-MA)/poly(N-isopropylacrylamide) hybrid hydrogels was designed and synthesized by solution polymerization. The xanthan-based precursor (Xan-MA) was prepared by substituting the hydroxyl groups in Xan by MA. This Xan-MA precursor was then polymerized with a known temperature sensitive precursor (N-isopropylacrylamide, NIPAAm) to form hybrid hydrogels with a series range of composition ratio of Xan-MA to NIPAAm precursors. These smart hydrogels were characterized by Fourier transform infrared spectroscopy for structural determination, differential scanning calorimertry for thermal property. And maximum swelling ratio, swelling kinetics and temperature response kinetics were studied. The data obtained clearly show that these smart hydrogels are responsive to the external changes of temperature as well as pH value. The magnitudes of smart and hydrogel properties of these hybrid hydrogels depend on the feed composition ratio of the two precursors. With the increase of the content of Xan-MA the maximum swelling ratio, reswelling ratio and thermo-sensitivities increase, and the feed composition ratio of Xan-MA/NIPAAm increases the maximum swelling ratio augment from 13.88 to 23.21. From XMN0, XMN1, XMN3 to XMN5, the lower critical solution temperatures (LCSTs) are 33.02, 36.15, 40.28 and 41.92 °, respectively. By changing the composition ratio of these two precursors, the LCST of the hybrid hydrogels could also be adjusted to be or near the body temperature for the potential applications in bioengineering and biotechnology fields.     

丙烯酸、甲基丙烯酸甲酯与苯胺三元共聚凝胶的制备及性能测定

报道了用溶液聚合法合成一类新型水凝胶丙烯酸、甲基丙烯酸甲酯与苯胺三元共聚凝胶.性能测定表明该三元共聚凝胶具有吸水性和盐敏感性;当pH值、温度、离子强度等外部环境变化时,出现体积相变.     

Laterally sandwich-typed hydrogel columns with liner poly(N-isopropylacrylamide) layer: Preparation, swelling/deswelling kinetics and drug delivery characteristics

A novel thermo-responsive hydrogel column, featured with both ends of linear poly(N-isopropylacrylamide) (PNIPAM) chains being grafted onto cross-linked PNIPAM chains, was reported. The laterally sandwich-typed hydrogel columns were fabricated by radical polymerization in a three-step process using a method of ice-melting synthesis. The initiating path, morphology and thermoresponsive characteristics of the prepared hydrogel columns were experimentally studied. The results show that the hydrogel column obtained by the initiator inside part has more quick swelling and deswelling rates responsing to temperature cycling than other hydrogels owing to linear PNIPAM chains to form supermacroporous structure. The proposed hydrogel structure provide a new mode of the phase transition behavior for thermo-sensitive "smart" or "intelligent" monodisperse micro-actuators, which is highly attractive for targeting drug delivery systems, chemical separations, and sensors and so on.